How To Install Styrofoam Insulation On A Home's Exterior



hi I'm Shannon from host improvements comm and in today's video I want to show you what I would do to add rigid insulation to the exterior of your home so basically you'd want to be doing this to improve the r-value obviously of your home and in our example today we're adding 2-inch XPS insulation to the outside now there's a few things you got to do ahead of time obviously you need to remove your old insulation or stuck or whatever you had on the wall replace and improve any imperfections or was in the old cheating if you have any those sorts of things okay and then there's a couple different ways you can go about the type are our this sorry the house wrap you could either have the house wrap like I do right against the wood of the house you can see the wood up here actually so I've got a shiplap style older home I've got the house wrap here which will be underneath the foam that's on the wall you can see the house are out there now you could put the foam on first and host wrap after really the the what I like why I like to do it this way is because when you fasten this over the foam sometimes if you don't get enough fasteners in it it's flapping and that sort of thing so it's here we still got our moisture barrier so the defame Meister gets through the foam which is very unlikely but if any does you still got your barrier on the plywood to protect the plywood so like I said you can do it either way I prefer to do it this way but I've done it both ways we're also using shiplap style foam if you look down here I've got a sheet here so the edges are actually ship lapped there's a half inch by one inch groove here so there's no joints that are lining right up that go directly back to the wall so we were kind of overlapping and reducing the chances of coal just transferring straight through those cracks so we talked about the house rack once you get that all on there's some other areas that can kind of be trouble areas for you that you need to deal with beforehand one would be in this case we've got existing windows this is case so we aren't changing our windows we're adding the foam to an existing wall so what's gonna happen because we've got two inch foam our foams actually going to be sticking out further past the windows and we've got another video showing how to deal with that to trim out the windows so that's that's one problem you can have the way around that is if you're changing your windows at the same time that's perfect what you would do is pull your old windows out and you would add basically a wood frame or a wood buck all the way around the opening the same thickness as the foam you're using so if I'm using 2 inch foam what I would normally do is I put a border of two by fours around that opening with a layer a half inch plywood on it to equal two inches and then that way then the window goes in and the window is totally out projecting past the foam and you don't have that issue you can just add your siding after like normal so that's that's a way around it but in this case we've we've got vinyl windows they're still in good shape and we're just leaving them in place other other problems you could run into is a situation like this where you've got your power your meter service or your power service on the outside of the home and as a homeowner or a DIY or anybody you don't you shouldn't be opening this or going in it to pull it off the wall to put foam behind it and even if you did honestly you couldn't really do it with this thick of foam because it would mean extending the wires the conduit would probably not even flex that far anyway so so kind of what you're stuck with is leaving this in place and working around it so in my case my my meter box here already had a piece of plywood behind it and it was just painted and the j-channel of the siding was butted up to it before so what I did is I put another piece of plywood down right to the bottom because all these pipe salts are too close I can't get two inch foam back here either so I just put another piece of 3/4 inch plywood to extend that plane down to the bottom and then I had some custom metal bent up that'll cover this all in when it's done so I've got this side done and you probably can't see it here's just a cut off I put a piece of flat back here and I got a custom piece bent up that's gonna sit against that plywood jogo to make up the difference from my styrofoam and then come across the face of the styrofoam a little bit just to just to create a more waterproof edge here so when when I go to put this side on it'll basically sit something like this and I'll screw it on and then my foam will tuck into it and then when all is said and done can you see this edge okay so when it's all said and done the foams behind there you've got this return of the metal here now when I go to do my siding I can actually just run my J channel right along here but my siding into it and end I'll to actually tape this to before the J channel goes on with a sheathing tape okay so that's how you you got to kind of invent some ways to work around some of this stuff that you can't move its permanently permanently fixed in place things like Vance receptacles lights that sort of thing you should be able to build those all out and pull them out to the exterior where they'd normally be on the plane of the wall and not have to most cases you never have to do something like this around those things they're usually movable but something like this that's fixed straight to the house there's not too much you can do with it without doing a major change so so when this is all said and done the sidings on there this will look nice and clean and finished it's maintenance-free and watertight do so okay now one of the other things I did in my case so I put my hoe strap on you can't actually see it but I had kind of an ugly groove in the old parching on the lower part of the wall I wanted to hide that so I've had to build out the wall a little bit to get down over top that edge so I'm actually lowering my starting point in my siding about an inch and a half on the house here so that I can hide that ugly mess that we're the old purging was so again to do that I decided because I'm dropping it so far I used to buy six material or five and a half inch material so that I can still get good fasteners up here into the wood into the rim joist of the house and this bottom part will just basically hang down over the over the purging and because I'm using two inch foam I used inch and a half material and some half inch OSB behind it just to equal my two inches because you can see here my foam is sitting right on top of that it just kind of it actually works so nice it creates a bit of a Ledge as well now if I come a little further down here and hopefully the camera can zoom enough because I've got my wrap running down behind this ledger board I also used a piece of membrane peel-and-stick membrane to help direct water across the face of this wood if it gets behind the foam and down and it'll run out behind the siding chances are you won't get much moisture back there but just in case you get a bit of conscience condensation or something you could also do this with a metal flashing if you wanted to get one mate made up you could do it that way I just find this stick-on membrane is easier you can flex and fold it to any profile that you need to so okay so that's on there our house wrap is all just stapled on as normal all the seams are taped and the house wrap is all taped to any of the windows or things that are protruding out you can see here so it's all sealed to keep water from running in behind it if it gets through there we've got this first piece on the wall we're using because of the two inch foam we're using three inch roofing nails and then I'm adding these little roofing washer to them you can buy longer nails like this with kind of a plastic cap already on them if that's cheaper than doing this in your area then there's no no problem with that at all but the idea is you need a little bigger head or a little bigger surface so when you you nail this on wind gets up it doesn't just rip it off this just holds a little better has a little more holding power you may not need the washer if you're putting your siding on almost immediately and you're not expecting any bigger winds you might be able to get away with just siding nails and and then putting your siding on right away because obviously your siding is all going to be nailed right through this as well now with your siding product if you're if you're using a siding you have to make sure you're using long enough nails as well because you need you can't just nail into this foam it'll never stay on there it'll just rip off so you need to make sure your nails your fasteners are going through the foam layer and at least you know three-quarters of an inch or so into the wood behind so I think that's pretty much got the basics covered maybe maybe we'll reposition the camera and I'll talk about what I did on the outside corners down here and then we'll get on with actually putting the foam on okay so on the corners what I do there's lots of guys that will just simply if you're using two inch foam they'll just run a 2×4 with a half inch piece of plywood up each side of the corner to give some good solid wood to nail your siding corner to the problem with that is now you've taken one of the worst areas of the house that's already got low r-value and you've added even more wood to it and added basically zero R value to it so what I like to do is wrap that corner in foam but then I go 1/2 inch less and thickness of foam on that and add 1/2 inch plywood over it so you basically have the foam against the corner giving you some r-value and then some half-inch plywood that allows you to still fasten your whatever type of corner you're using into some actual wood it's something I prefer to do I've seen people just run their styrofoam around that corner and put the corner right on it it probably works ok I'm just a little leery that especially when you're using two-inch the problem with a normal vinyl siding corner is you might be able to nail one side good but the other side is going to be probably not even hit any wood it's even no matter how long a nail you used because it's moved the corner out so much you're just nailing totally into foam and to me I'm not sure that that'll stay on there long-term so so I like to have some wood to fasten the corner to so again so in our case we're using two inch foam here so I've got inch and a half foam wrap just around the corner about six inches ease each way then I mailed a piece of half-inch plywood OSB whatever over top of it and that forms my corner now I just butt into that with my with my foam sheets on the wall you can kind of see around this corner basically what we're gonna have as a finished effect so we've got our our outside corners here and then we've got our vinyl siding covering the wall and you might even be able to see kind of the window detail a little bit up there too so now in my other video we'll be dealing with the window detail showing you how to do that so we'll cover that later okay I think we'll get repositioned like I said we've got the one piece on the wall now we're gonna cut this next piece so I'll show you how to make all the cuts and we'll put it on the wall okay so when you're gonna measure around obstacles it's like anything else you're just picking your point to measure off of so in this case I would use this sheet and I'm measuring right to the edge as the window and then up from the ledger of the window or ledger on the bottom to the bottom of the window and then if you have something at that end to you can measure there I've marked all those measurements out on here you can see the black lines I'm going to cut those out as well as because of how I'm starting and the and the shiplap on the foam I need to cut that bottom lip off so that I've got full two inches of foam sitting down on here okay so that might be what I do first so I'm just gonna stand my sheet up and maybe you'll be able to see this a little better if I turn it here I don't get too close to you so you can see my my lip that I've got there this is the surface I want out facing out on the wall so I need to cut this lip off so that we rate down at this edge now simplest way tis is to use a sharp bleeded utility knife that extends like this just lay it on there nice and far and if you make kind of one pass first it just kind of gets you started you're just laying you're using this as a guide to get you so you're not tilted too much hopefully just laying flat on there and just pulling the knife through it so then if you just make a couple more cuts it should come out the other side and you should end up with a pretty darn flat cut and if you don't just trim it up a little bit so I'll just do the rest of this one the sharper sharper blade you have the better so other ways that you can things you can do for cutting this you could use a circular saw you could use the table saw the knife is by far the quickest you can even use a handsaw like a drywall saw or a wood saw or anything if you've got a drill round holes you can still use like cut saws on it pull saws that sort of thing so okay so we got that cut off now we've got this upper notch we need to cut out for the window there and I've got it marked out I'll just use my straight edge here once we kind of get it scored and you've got that line to help your blade fall you really don't need the straight edge after that so I'm not trying to cut all the way through on the first pass those hawks don't like us working here today I'm just gonna make a few passes like I did on the automatic now you when you've got that bleed out so far you got to be really careful where the rest of your limbs are that breaks off or you slip that is going to cut you bad okay and the same thing up these edges I'm just going to freehand that just trying to cut a square as I can same thing at this end don't be afraid to make multiple passes if you try to force it too much that's when you're gonna slip and cut yourself prob'ly okay so we've got our piece out of there you can see that it does a pretty nice job you're gonna get some little fuzzy edges or whatever but as long as you're fairly square everything should work out and fit fit nicely and we've got the shiplap edge here so on this sheet the ship laps hanging out on the front edge on the sheet we're going up against this long edge is on the back so they overlap each other so we'll just give this a try see if it fits [Applause] and it's gonna be a little tight actually I've got to cut some off that in so I'm gonna cut this to length and then we'll put it up okay so we got this trimmed up now you should be able just put that rate in place don't worry if you're got a little bit of a gap there if you get any gaps like that you can go around with some spray foam and fill those in as long as it's fitting okay and so I'm gonna use these nails with the big washers on and this home has three quarter-inch shiplap on it as we talked about before so I'm not really worried about hitting studs or anything if you can preferably try to hit the studs if you've just got us with plywood on it but it's pretty tough to really get that all to work out but and because we're gonna be siding and not too long of a time period I'm not going to crazy with the nails as you can see I basically got all I'll have eight nails on that one I I'm one short right now but if you're not going to be putting anything else over it for a while you probably I would say you should have a dozen nails on that okay and you can see I I stayed away from this back edge because this one's over lapping this one so now I can put this nail here and it kind of pinches that one in place just hammer those in just so they basically flatten out to the surface of the form [Applause] unbent okay so we've got those pieces on I've pre-cut the two larger pieces here which is all I'm gonna put on for the video sake you would also fill in above the window there's a little strip up there you can see that will be missing after that you would normally fill in the same is above this window and a little strip here now you're as you go through the process of doing this like I said this is all shiplap types foam you're gonna have the odd joint where there isn't the shiplap finish and it's not a huge deal but you know try to use as many of the factory shiplap edges as you can and we're gonna tape the joints as well okay so like I said you should go and fill in all those spots and I will after but I just for the sake of the time of the video I just want to continue on here so when you get some spots like this I've got a little bit of a wavy cut you can take some spray foam and just spray that gap in if you want it's not in my mind a hundred percent necessary that that the gaps are completely sealed tight but you know you don't want anything say any bigger than an eighth of an inch now the next step would be to go around and tape any seams that you have and really the right way to do it is do all your lower seams and then work your way up so that the tape here is overlapping the tape there it's not that big of an issue in this situation but that is the way you should do it so we're just using its white but it's really just regular house wrap type tape let's put it on make sure it's stuck you don't need to worry about taping the nails for this just get all your seams taped up and then you should be fine now normally I because we've taped the host wrapping behind to the window I don't feel there's any reason to be taping here now you can't really tape to this because it's going to be seen and if you watch the other video I talked about you'll see how I add the trim onto here too to hide this difference where the foam sticks out from the window I think that pretty much should wrap it up can't think of anything else so if you think of something that you had a question for you can always go to our forum and post your question there and we can surely answer you from there if you aren't familiar with house improvements like them subscribe to our Channel and then you'll be notified anytime we do put a video out you can look at all the other content that we have if you want to help support us a little extra to keep making these videos that you're watching you can also maybe check out our patreon and become a supporter there as well so anyways thank you for watching and I look forward to you watching the next one

20 Comments

  • M.D.W GAMING

    April 13, 2019

    1st of all I love your videos.
    And thank you for your wisdom. I have a question. Should I install some plywood then the moisture Barrier and then the foam?

    Reply
  • Christina Hagerman

    April 13, 2019

    Thank you for the video. Getting ready to re-side my house (or part of it for now). I had a couple questions, but you cleared them up for me.

    Reply
  • N Holt

    April 13, 2019

    Will condensation get behind the foam?

    Reply
  • N Holt

    April 13, 2019

    How come all these guys sound like they are from Canada?

    Reply
  • Matt C

    April 13, 2019

    Beautiful work my friend!

    Reply
  • Sawyer Ramos

    April 13, 2019

    wait! what if the house is cynder blocks do u still need moister barriers?

    Reply
  • Clyde Livingston

    April 13, 2019

    is exterior insulation vital? Building a house in NC, mild temps, should I do the exterior or just stick with 2' by 4' studs and fiberglass insulation in the gaps?

    Reply
  • Ralph Wease

    April 13, 2019

    If I’m wrapping the exterior of the house with 2” of foam do I still need a vapor barrier on the inside of the house? I live in Alaska and our vapor barrier is behind the Drywall. I’m wondering how will the wall cavity breathe, or does it even need to? Great video!

    Reply
  • ron prize

    April 13, 2019

    Shannon good video, you could've built a box of the 2" foam around, at least, the conduit part, of the meter box, just an Idea. I've been an electrician, for 30 years, there's no safety issue, in doing it, as I suggested. It just might help keep a little more air in.

    Reply
  • renodeify

    April 13, 2019

    Taping the house wrap to the bottom window trim is probably a bad idea. If there is a leak around the trim, it will funnel water right to the sheathing. But then that's probably the best you can do without taking the windows and redoing the sill pan.

    Reply
  • Grateful aya

    April 13, 2019

    my city code says we have to put the house wrap over the foamboard or OSB

    Reply
  • rob bacon

    April 13, 2019

    Im going to be doing this to my house from 1920. The toung and groove sheething is not as reliable as i would like it to be . Can i go over it with 3/4 inch osb, or plywood, in order to have have something secure to screw into. Or would i have to remove the old sheething and start from the beams?

    Reply
  • TangoX

    April 13, 2019

    I tape a cross of duct tape where I screw in a 3" screw over a standard metal washer to protect the the (pink) foam from breaking and allow the screw to sit below the surface before I hang the sheet metal or whatever covering you're using. All this is better than painting the exterior plywood and covering up the thermal bridges. As for cutting the foam, I hate the toxic foam particles flying everywhere. I use a long sharp blade over a surface where I can see the particles and pick them up with roller tape or vacuum; including the rough surface of the foam board after cutting.

    Reply
  • Alex Baldwin

    April 13, 2019

    Can you do a video of metal bending please

    Reply
  • lloyd morel

    April 13, 2019

    great vid, thanks

    Reply
  • Thaylor Harmor

    April 13, 2019

    No roller on the seams?

    Reply
  • Thaylor Harmor

    April 13, 2019

    Why no furring strips?

    Reply
  • David Searles

    April 13, 2019

    what material did you use at the corner of the building over the 1/2" OSB? That combined with the J channels looks a lot better than the corners they sell that accepts the siding without using J channels. They always look so flimsy.

    Reply
  • Milosz Stodulski

    April 13, 2019

    Styrofoam in Europe has lower R value han Graphite polystyrene. Comes in sizes, standards, 1000mm x 500mm and PU foam is filled in-between the sheets, where jointing occurs.

    Reply
  • ducebigalow

    April 13, 2019

    Some window manufacturers (Vinylguard in Canada) have a extended brick mould that allows for up to 2" insulation.  This sets the actual thermal glass into the wall and not on the exterior of the wall.  They also have optional jamb extensions for the inside allowing it to be flush with drywall.

    Reply

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